Sorption kinetics and intraparticulate diffusivities of Cd, Pb and Zn ions on maize cob

Abstract

The kinetics of sorption and intraparticulate diffusivities of Zn, Cd and Pb using maize cob was studied. The amount of the metal ions adsorbed increased with time. The highest sorption rates of the three metal ions were 71% for Z²⁺, 32% for Cd²⁺, and 30% for Pb²⁺. The fractional attainment of equilibrium showed that Zn²⁺ reached equilibrium before Pb²⁺ ion and then Cd²⁺ ion. This study showed that the sorption of Zn²⁺, Cd²⁺ and Pb²⁺ ions on maize cob is particle diffusion controlled. The rate coefficients for particle diffusion were 0.07 min^-1 for Zn²⁺, 0.053min^-1 for Pb²⁺ and 0.081min^-1 for Cd²⁺.

African Journal of Biotechnology Vol. 4 (6), pp. 509-512, 2005